Telecommunications apparatus and methods

ABSTRACT

A wireless telecommunication system comprises a base station and a terminal device (UE). The UE is configured to determine its mobility status and an associated reliability, e.g. an indication of the extent to which the UE is moving and the confidence in this determination. In some cases the reliability may be based on how the UE determined its mobility status. For example, if the UE determined itself to be of relatively low mobility because it has an internal configuration setting indicating it is deployed in a fixed position, the reliability of this mobility status may be considered to be greater than if the UE determined itself to be of relatively low mobility because it has not recently undergone many base station handovers. The UE is configured to convey an indication of the mobility status and the reliability to the base station. The base station may then configure the UE for operation within the wireless telecommunications system in a manner that takes account of both the mobility status and the reliability for the mobility status. This can help optimise configuration settings for the UE which depend on device mobility.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/109,765, filed Jul. 5, 2016, which is based on PCT filingPCT/EP2014/077396, filed Dec. 11, 2014, and claims priority to EP14153010.5, filed Jan. 29, 2014, the entire contents of each areincorporated herein by reference.

BACKGROUND Field

The present disclosure relates to telecommunications apparatus andmethods. In particular, certain embodiments relate to schemes forcommunicating information regarding the mobility status of a terminaldevice in a wireless telecommunications system.

Description of Related Art

The “background” description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent it is described in thisbackground section, as well as aspects of the description which may nototherwise qualify as prior art at the time of filing, are neitherexpressly or impliedly admitted as prior art against the presentinvention.

Wireless communication systems have evolved over the past ten years orso from the GSM System (Global System for Mobile communications) to the3G system and now include packet data communications as well as circuitswitched communications. The third generation partnership project (3GPP)is developing a fourth generation wireless communication system referredto as Long Term Evolution (LTE) in which a core network part has beenevolved to form a more simplified architecture based on a merging ofcomponents of earlier wireless radio network architectures and a radioaccess interface which is based on Orthogonal Frequency DivisionMultiplexing (OFDM) on the downlink and Single Carrier FrequencyDivision Multiple Access (SC-FDMA) on the uplink.

Third and fourth generation wireless telecommunication systems, such asthose based on the 3GPP defined UMTS and Long Term Evolution (LTE)architecture are becoming able to support a wider range of services thansimple voice and messaging services offered by previous generations ofwireless telecommunication systems. For example, with the improved radiointerface and enhanced data rates provided by LTE systems, a user isable to enjoy high data rate applications such as wireless videostreaming and wireless video conferencing that would previously onlyhave been available via a fixed line data connection.

The deployment of third and fourth generation networks has also led tothe parallel development of new classes of devices and applicationswhich, rather than taking advantage of the high data rates available,instead take advantage of the robust radio interface and increasingubiquity of the coverage area. Examples include so-called machine typecommunication (MTC) applications, some of which are in some respectstypified by semi-autonomous or autonomous wireless communication devices(MTC devices) communicating small amounts of data on a relativelyinfrequent basis. Examples include so-called smart meters which, forexample, are located in a customer's home and periodically transmit databack to a central MTC server relating to the customer's consumption of autility such as gas, water, electricity and so on. Smart metering ismerely one example of potential MTC device applications. Furtherinformation on characteristics of MTC-type devices can be found, forexample, in the corresponding standards, such as ETSI TS 122 368 V11.6.0(2012-09)/3GPP TS 22.368 version 11.6.0 (Release 11) [1]. Some typicalcharacteristics of MTC type terminal devices/MTC type data mightinclude, for example, characteristics such as low mobility, high delaytolerance, small data transmissions, a level of predictability fortraffic usage and timing (i.e. traffic profile), relatively infrequenttransmissions and group-based features, policing and addressing.

It has been recognised that it can in some circumstances be beneficialfor terminal devices to be configured to operate differently withinwireless telecommunication systems according to their particularcharacteristics. One such characteristic which can impact the optimumconfiguration parameters for a terminal device is the extent to whichthe terminal device is expected to move within the wirelesstelecommunications network, for example in terms of how frequently theterminal device is expected to be handed over from one base station toanother. This consideration can be particularly important for MTC-typecommunications devices since it is expected that certain types of suchdevices will often have low no mobility, for example because they areinstalled in a fixed location for an extended period of time.

To help take account of the extent to which terminal devices are movingwithin a wireless telecommunications network it is known in UMTS forterminal devices to provide a base station with an estimation for theirmobility status, and work is currently in progress for including thisfunctionality to LTE also. See, for example, ETSI TS 136 304 V11.5.0(2013-09)/3GPP TS 36.304 version 11.5.0 (Release 11) [2] and ETSI TS 136331 V11.5.0 (2013-09)/3GPP TS 36.331 version 11.5.0 (Release 11) [3].

LTE systems currently incorporate three mobility states, namely normalmobility, medium mobility, and high mobility and UMTS systemsincorporate two mobility states, namely normal mobility and highmobility. The mobility state for a given terminal device is determinedby counting cell reselections for the terminal device within a giventimeframe. For example, in accordance with LTE proposals the defaultmobility for a terminal device is normal mobility. However, if aterminal device undergoes more than a first threshold number of cellreselections but less than a second threshold number of cellreselections in a particular time period the terminal device mobilitystatus is changed to medium mobility. If the terminal device undergoesmore than the second threshold number of cell reselections in theparticular time period, the terminal device mobility status is changedto high mobility. A terminal device will return to normal mobilitystatus if the relevant threshold number of cell reselections are notexceeded within a given time period. The mobility status of a terminaldevice can impact the parameters considered when determining whether theterminal devices to move from one base station to another. The mobilitystatus of a terminal device may be reported to the base station using a“UE mobility state indicator” in RRC Connection Request or Cell Updatemessage signalling in UMTS. The network may then set mobility parametersfor the terminal device accordingly. In LTE the mobility status of aterminal device may be used for scaling of mobility parameters in idleand connected mode. Further information on mobility states and scalingin accordance with existing proposals can be found in the relevantstandards, for example in Sections 5.2.4.3 (“Mobility States of a UE”)and 5.2.4.3.1 (“Scaling rules”) in ETSI TS 136 304 V11.5.0(2013-09)/3GPP TS 36.304 version 11.5.0 (Release 11) [2], the entirecontents of which are incorporated herein by reference.

There are also currently ongoing discussions regarding the increased useof mobility status information in wireless telecommunications systems.For example, within an LTE HetNet (heterogeneous network) context workis currently being done in order that the mobility status of a terminaldevice may be reported to the base station using a “mobilityState”identifier in “RRCConnectionSetupComplete” and within an LTE or UMTSMTC-device context.

As noted above, mobility state estimates (MSE) are generally based on acount of cell reselection/handover events occurring within a giventimeframe. However, the inventors have recognised this process can beprone to inaccuracies. For example, mobility state estimation is broadlyintended to provide an indication of the speed of a terminal device bycalculating cell changes over a period of time. However, factors otherthan speed can give rise to cell changes, for example changing cellcoverage or cells of different coverage (sizes), fading channelconditions, terminal device measurement errors, and reselection/handoverparameter settings can affect the accuracy of mobility state estimates.The inventors have further recognise these issues can be particularlysignificant when seeking to determine the mobility state of a stationaryor near stationary terminal device. This is an important issue becausethere can be significant differences in the most appropriateconfiguration parameters for low-mobility/stationary terminal devices ascompared to terminal devices which have higher mobility. For example, ifa terminal device is stationary or slow-moving, it can be more radioefficient to maintain the terminal device in a connected mode (therebyreducing the overhead of RRC connection establishment signalling) forrelatively long periods than if a terminal device is moving more quickly(because of the increased handover signalling associated with a moremobile terminal device). In addition, longer and deeper power savingstates can generally be configured for a terminal device which isstationary than would be appropriate for a terminal device which is moremobile. However, because of the difficulties associated with accuratelydetermining a terminal device's mobility status in a wirelesstelecommunications network it may be difficult to optimally configureterminal devices according to their mobility status.

There is therefore a need for improved schemes for communicatinginformation regarding the mobility status of a terminal device in awireless telecommunications system.

SUMMARY

According to a first aspect of the present disclosure, there is provideda method of operating a terminal device for communicating with a basestation in a wireless telecommunications system, the method comprising:determining a mobility status for the terminal device and an associatedreliability for the determined mobility status; conveying an indicationof the mobility status and an indication of the reliability for themobility status to the base station; and configuring the terminal devicefor operation within the wireless telecommunications system in a mannerthat takes account of both the mobility status and the reliability forthe mobility status.

According to a second aspect of the present disclosure, there isprovided a terminal device for communicating with a base station in awireless telecommunications system, wherein the terminal devicecomprises a controller unit and a transceiver unit configured to operatetogether to determine a mobility status for the terminal device and anassociated reliability for the determined mobility status; to convey anindication of the mobility status and an indication of the reliabilityfor the mobility status to the base station; and to configure theterminal device for operation within the wireless telecommunicationssystem in a manner that takes account of both the mobility status andthe reliability for the mobility status.

According to a third aspect of the present disclosure, there is providedcircuitry for a terminal device communicating with a base station in awireless telecommunications system, wherein the circuitry comprises acontroller element and a transceiver element configured to operatetogether to cause the terminal device to determine a mobility status forthe terminal device and an associated reliability for the determinedmobility status; to convey an indication of the mobility status and anindication of the reliability for the mobility status to the basestation; and to configure the terminal device for operation within thewireless telecommunications system in a manner that takes account ofboth the mobility status and the reliability for the mobility status.

According to a fourth aspect of the present disclosure, there isprovided a method of operating a base station for communicating with aterminal device in a wireless telecommunications system, the methodcomprising: receiving from the terminal device an indication of adetermined mobility status for the terminal and an indication of anassociated reliability for the mobility status; and configuring theterminal device for operation within the wireless telecommunicationssystem in a manner that takes account of both the mobility status andthe reliability for the mobility status.

According to a fifth aspect of the present disclosure, there is provideda base station for communicating with a terminal device in a wirelesstelecommunications system, wherein the base station comprises acontroller unit and a transceiver unit configured to operate together toreceive from the terminal device an indication of a determined mobilitystatus for the terminal and an indication of an associated reliabilityfor the mobility status; and to configure the terminal device foroperation within the wireless telecommunications system in a manner thattakes account of both the mobility status and the reliability for themobility status.

According to a first aspect of the present disclosure, there is providedcircuitry for a base station communicating with a terminal device in awireless telecommunications system, wherein the circuitry comprises acontroller element and a transceiver element configured to operatetogether to cause the base station to receive from the terminal devicean indication of a determined mobility status for the terminal and anindication of an associated reliability for the mobility status; and toconfigure the terminal device for operation within the wirelesstelecommunications system in a manner that takes account of both themobility status and the reliability for the mobility status.

Further respective aspects and features are defined by the appendedclaims.

The foregoing paragraphs have been provided by way of generalintroduction, and are not intended to limit the scope of the followingclaims. The described embodiments, together with further advantages,will be best understood by reference to the following detaileddescription taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the disclosure and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings wherein likereference numerals designate identical or corresponding parts throughoutthe several views, and wherein:

FIG. 1 provides a schematic diagram illustrating an example of awireless telecommunication system;

FIG. 2 schematically represents a wireless telecommunications systemaccording to an embodiment of the disclosure; and

FIG. 3 is a signalling ladder diagram representing communicationsbetween a base station and a terminal device operating in accordancewith an embodiment of the disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 provides a schematic diagram illustrating some basicfunctionality of a wireless telecommunications network/system 100operating in accordance with LTE principles and which may be adapted toimplement embodiments of the disclosure as described further below.Various elements of FIG. 1 and their respective modes of operation arewell-known and defined in the relevant standards administered by the3GPP (RTM) body and also described in many books on the subject, forexample, Holma H. and Toskala A [4]. It will be appreciated thatoperational aspects of the telecommunications network which are notspecifically described below may be implemented in accordance with anyknown techniques, for example according to the relevant standards.

The network 100 includes a plurality of base stations 101 connected to acore network 102. Each base station provides a coverage area 103 (i.e. acell) within which data can be communicated to and from terminal devices104. Data is transmitted from base stations 101 to terminal devices 104within their respective coverage areas 103 via a radio downlink. Data istransmitted from terminal devices 104 to the base stations 101 via aradio uplink. The core network 102 routes data to and from the terminaldevices 104 via the respective base stations 101 and provides functionssuch as authentication, mobility management, charging and so on.Terminal devices may also be referred to as mobile stations, userequipment (UE), user terminal, mobile radio, and so forth. Base stationsmay also be referred to as transceiver stations/nodeBs/e-nodeBs, and soforth.

FIG. 2 schematically shows a telecommunications system 500 according toan embodiment of the disclosure. The telecommunications system 500 inthis example is based broadly on a LTE-type architecture. As such manyaspects of the operation of the telecommunications system 500 arestandard and well understood and not described here in detail in theinterest of brevity. Operational aspects of the telecommunicationssystem 500 which are not specifically described herein may beimplemented in accordance with any known techniques, for exampleaccording to the established LTE-standards and known variations thereof.

The telecommunications system 500 comprises a core network part (evolvedpacket core) 502 coupled to a radio network part. The radio network partcomprises a base station (evolved-nodeB) 504, a first terminal device506 and a second terminal device 508. It will of course be appreciatedthat in practice the radio network part may comprise a plurality of basestations serving a larger number of terminal devices across variouscommunication cells. However, only a single base station and twoterminal devices are shown in FIG. 2 in the interests of simplicity.

As with a conventional wireless radio network, the terminal devices 506,508 are arranged to communicate data to and from the base station(transceiver station) 504. The base station is in turn communicativelyconnected to a serving gateway, S-GW, (not shown) in the core networkpart which is arranged to perform routing and management of wirelesscommunications services to the terminal devices in thetelecommunications system 500 via the base station 504. In order tomaintain mobility management and connectivity, the core network part 502also includes a mobility management entity (not shown) which manages theenhanced packet service, EPS, connections with the terminal devices 506,508 operating in the communications system based on subscriberinformation stored in a home subscriber server, HSS. Other networkcomponents in the core network (also not shown for simplicity) include apolicy charging and resource function, PCRF, and a packet data networkgateway, PDN-GW, which provides a connection from the core network part502 to an external packet data network, for example the Internet. Asnoted above, the operation of the various elements of the communicationssystem 500 shown in FIG. 2 may be broadly conventional apart from wheremodified to provide functionality in accordance with embodiments of thedisclosure as discussed herein.

In this example, it is assumed the first terminal device 506 is aconventional smart-phone type terminal device communicating with thebase station 504. Thus, and as is conventional, this first terminaldevice 506 comprises a transceiver unit 506 a for transmission andreception of wireless signals and a controller unit 506 b configured tocontrol the smart phone 506. The controller unit 506 b may comprise aprocessor unit which is suitably configured/programmed to provide thedesired functionality using conventional programming/configurationtechniques for equipment in wireless telecommunications systems. Thetransceiver unit 506 a and the controller unit 506 b are schematicallyshown in FIG. 2 as separate elements. However, it will be appreciatedthat the functionality of these units can be provided in variousdifferent ways, for example using a single suitably programmed generalpurpose computer, or suitably configured application-specific integratedcircuit(s)/circuitry. As will be appreciated the conventional terminaldevice 506 will in general comprise various other elements associatedwith its operating functionality.

In this example, it is assumed the second terminal device 508 is amachine-type communication (MTC) terminal device according to anembodiment of the disclosure. As discussed above, MTC devices may betypically characterised as semi-autonomous or autonomous wirelesscommunication devices communicating small amounts of data. Examplesinclude so-called smart meters which, for example, may be located in acustomer's house and periodically transmit information back to a centralMTC server data relating to the customer's consumption of a utility suchas gas, water, electricity and so on. MTC devices may in some respectsbe seen as devices which can be supported by relatively low bandwidthcommunication channels having relatively low quality of service (QoS),for example in terms of latency. It is assumed here the MTC terminaldevice 508 in FIG. 2 is such a device. It will, however, the appreciatedthat embodiments of the disclosure may also be implemented for othertypes of terminal device.

As with the smart phone 506, the MTC device 508 comprises a transceiverunit 508 a for transmission and reception of wireless signals and acontroller unit 508 b configured to control the MTC device 508. Thecontroller unit 508 b may comprise a processor unit which is suitablyconfigured/programmed to provide the desired functionality describedherein using conventional programming/configuration techniques forequipment in wireless telecommunications systems. The transceiver unit508 a and the controller unit 508 b are schematically shown in FIG. 2 asseparate elements for ease of representation. However, it will beappreciated that the functionality of these units can be provided invarious different ways, for example using a single suitably programmedgeneral purpose computer, or suitably configured application-specificintegrated circuit(s)/circuitry, or using a plurality of discretecircuitry/processing elements for providing different elements of thedesired functionality. It will be appreciated the MTC device 508 will ingeneral comprise various other elements associated with its operatingfunctionality in accordance with established wireless telecommunicationstechniques (e.g. a power source, possibly a user interface, and soforth).

The base station 504 comprises a transceiver unit 504 a for transmissionand reception of wireless signals and a controller unit 504 b configuredto control the base station 504. The controller unit 504 b may comprisea processor unit which is suitably configured/programmed to provide thedesired functionality described herein using conventionalprogramming/configuration techniques for equipment in wirelesstelecommunications systems. The transceiver unit 504 a and thecontroller unit 504 b are schematically shown in FIG. 2 as separateelements for ease of representation. However, it will be appreciatedthat the functionality of these units can be provided in variousdifferent ways, for example using a single suitably programmed generalpurpose computer, or suitably configured application-specific integratedcircuit(s)/circuitry or using a plurality of discretecircuitry/processing elements for providing different elements of thedesired functionality. It will be appreciated the base station 504 willin general comprise various other elements associated with its operatingfunctionality. For example, the base station 504 will in generalcomprise a scheduling entity responsible for scheduling communications.The functionality of the scheduling entity may, for example, be subsumedby the controller unit 504 b.

Thus, the base station 504 is configured to communicate data with thesmart phone 506 over a first radio communication link 510 andcommunicate data with the MTC device 508 over a second radiocommunication link 512. Both radio links may be supported within asingle radio frame structure associated with the base station 504. It isassumed here the base station 504 is configured to communicate with thesmart phone 506 over the first radio communication link 510 inaccordance with the established principles of LTE-based communicationsand to communicate with the MTC-device 506 over the second radiocommunication link 512 in accordance with embodiments of the disclosureas described herein. It will be appreciated the base station may readilyobtain information indicating the different classes of terminal devicewhich are attached to the base station in accordance with conventionaltechniques. That is to say, the base station will be aware that thesmart phone is of a device class that includes conventional smartphonesand the MTC device is of a device class that includes MTC devices.

As noted above it is known for a terminal device to provide a basestation with an indication of an estimated mobility status for theterminal device. However, as also noted above, it is difficult for abase station to fully optimise a terminal devices configuration withinthe network according to its mobility status because of the potentialfor inaccuracies in the estimated mobility status. To address theseissues in accordance with embodiments of the disclosure it is proposedthat a terminal device provides a base station with an indication of theaccuracy of a reported mobility status to be used in conjunction withthe mobility status for configuring the terminal device for operation inthe wireless telecommunications system. In this regard a terminal devicemay be configured to determine its mobility status using differentmethods from those currently used (i.e. those based on counting cellreselections/handovers) and to in effect indicate to the base stationwhen providing an indication of its mobility status which method wasused.

For example, a terminal device may be configured to have the ability todetermine and report its mobility status based on cellreselection/handover counting in the normal way. However, the terminaldevice may be further configured to recognise if it has been connectedto a docking station/fixed power supply, and so will remain stationaryfor as long as it remains connected. Thus, while the terminal device isconnected to the docking station/fixed power supply the terminal devicecould indicate to the base station that the mobility status of theterminal device is that it has low mobility (or is stationary if this isone of the available mobility status levels adopted in a givenimplementation), and furthermore this mobility status determination hasa high degree of accuracy because it is based on the terminal devicebeing physically coupled to an element at a fixed location (i.e. thedocking station or power supply). The base station is thus made awarethat the terminal device has low mobility/is stationary, and furthermorethere is a high degree of certainty in this determination. The basestation may therefore proceed to configure the operation of the terminaldevice in a manner which is appropriate for a terminal device which isknown to be stationary. If the terminal device is removed from thedocking station it may proceed to provide an updated mobility status andassociated reliability indication to the base station based on cellreselection handover counting in the normal way. That is to say, theterminal device may indicate to the base station that it appears to havelow mobility and that this is based on counting cellreselection/handover events. The base station is thus made aware thatthe terminal device is reporting that it has low mobility/is stationary,but there is a higher degree of uncertainty in this determination ascompared to when the terminal device mobility state is determined basedon it being coupled to an element in a fixed location. The base stationmay therefore proceed to configure the operation of the terminal devicein a manner which is appropriate for a terminal device which thought tohave relatively low mobility, but in fact might have a higher degree ofmobility.

There are various different ways in which a terminal device mayestablish its mobility and these may be associated with different levelsof reliability. For example, in one implementation a terminal device maybe able to measure its position (and hence determine its mobility) usingglobal positioning satellite (GPS) techniques, or any other knowntechniques for determining position, known to be associated with a givendegree of reliability. In another example a terminal device may beassociated with a fixed device property indicating its mobility. Forexample, a terminal device comprising an MTC-type device such as a smartmeter, vending machine or security camera, installed at a fixed locationmay be configured with the device property “stationary”. Thus a terminaldevice providing a base station with an indication of this deviceproperty is in effect providing the base station with an indication ofits mobility status and an associated reliability (i.e. high reliabilitybecause the terminal device is in fact intended to operate in a fixedlocation).

FIG. 3 is a signalling ladder diagram schematically representing modesof operation for the terminal device 508 and the base station 504schematically represented in FIG. 2 in accordance with some embodimentsof the present disclosure. As already noted above, aspects of theoperation of a wireless telecommunications system in accordance withembodiments of the disclosure, for example as represented in FIGS. 2 and3, which are not specifically described herein may be implemented inaccordance with any conventional techniques.

It is assumed the processing represented in FIG. 3 starts at a time whenthe terminal device 508 is in an idle mode of operation, but willshortly request to move to a connected mode of operation. As is wellunderstood, in an LTE type network there are two Radio Resource Control(RRC) modes for terminal devices, namely: (i) RRC idle mode (RRC_IDLE);and (ii) RRC connected mode (RRC_CONNECTED). To receive user-plane dataa terminal device must be in RRC connected mode and the terminal devicedoes not receive user-plane data in RRC idle mode. In RRC idle mode, thecore network (CN) part of the wireless telecommunications systemrecognizes the terminal device is present within the network, but theradio access network (RAN) part of the wireless telecommunicationssystem does not. In effect, in an RRC idle mode the terminal device isnot connected to the base station. The process of going from RRC idlemode to RRC connected mode may be referred to as connecting to a cell.The specific reason for the terminal device seeking to transition fromidle mode to connected mode in the present example is not significant.

Thus, in step S1 of the processing represented in FIG. 3 the terminaldevice 508 receives system information from the base station 504 whilein idle mode in accordance with the principles underlying conventionaltechniques for receiving system information in wirelesstelecommunications systems. The system information may include anindication as to whether or not mobility status reporting in accordancewith embodiments of the disclosure is currently implemented. This may beindicated, for example, through the introduction of an new informationelement in one of the SIBS comprising the system information and whichmay be set as a “flag” to indicate whether modified mobility statusreporting is implemented. In this example it is assumed that the systeminformation received by the terminal device in step S1 indicates thatmobility status reporting in accordance with embodiments of thedisclosure is currently being supported by the base station 504.However, in other example implementations such reporting may be apermanent feature of the network operation such that it is notspecifically indicated as being activated in system information, or anindication that such reporting is active may be provided in conjunctionwith other signalling, for example in conjunction with a modifiedversion of the RRC connection setup signalling of step S3 discussedfurther below.

In step S2 the terminal device 508 transmits radio resource control(RRC) connection request signalling to the base station to indicate adesire to transition from idle mode to connected mode. As noted above,the specific reason why the terminal device 508 wishes to make thistransition is not significant to the principles underlying thedisclosure. The RRC connection request of step S2 may be performed inaccordance with conventional techniques.

In step S3 the base station 504 transmits RRC connection setupsignalling back to the terminal device 508 in response to receiving theRC connection request signalling step S2. The RRC connection setupsignalling of step S3 may be based on conventional techniques.

In step S4 the terminal device establishes a mobility stateestimate/mobility status and determines a reliability for the determinedmobility status. As noted above, the terminal device may be providedwith multiple different ways of establishing its mobility status, anddifferent degrees of reliability may be associated with the differentways of establishing the mobility status. Typically the terminal devicewill seek to determine its mobility status, and the associatedreliability, based on what is considered to be most reliable techniquecurrently available to the terminal device.

For example, assume for the sake of one specific example a terminaldevice is able to establish its mobility status based on historical cellreselection events during the time it was in idle mode in accordancewith conventional techniques (relatively low reliability) and is alsoable to recognise it has low mobility (with high reliability) when it isconnected to a docking station. If this terminal device it is not in thedocking station during step S4, it will establish its mobility status(mobility state estimate) based on counting cell reselections inaccordance with a conventional techniques, and having relatively lowreliability. If, on the other hand, in step S4 the terminal device is inthe docking station, it will establish its mobility status (i.e. lowmobility/stationary) based on this fact, and wherein this will beestablished with a relatively high degree of reliability.

In step S5 the terminal device 508 transmits RRC connection setupcomplete signalling to the base station 504. This signalling may bebroadly based on conventional techniques for providing RRC connectionsetup complete signalling, but whereas conventional RRC connection setupcomplete signalling may include an indication of mobility status(mobility state estimation), the RRC connection setup completesignalling of step S5 in accordance with an embodiment of the disclosureconveys both an indication of the mobility status established in step S4and an indication of the reliability of the mobility status.

The specific characterisation of the reliability of the mobility statusmay be provided in a number of different ways. For example, differentdegrees of reliability may be associated with different indices and theterminal device may provide an indication of the relevant index inassociation with its mobility status indication. In one example theindices may simply represent a binary indication of whether the mobilitystatus is to be considered to have a high or a low reliability. Forexample, the different manners in which the terminal device mayestablish its mobility status may be associated with high or lowreliability according to a predefined scheme. In another example theindication of MSE reliability conveyed by the terminal device may simplybe an indication of the method by which the associated mobility statushas been determined. In yet another example implementation a terminaldevice is able to determine its mobility status from an inherent deviceproperty (e.g. the terminal device is in effect programmed/hardwired asa “stationary” device). The base station may have access to a tablelinking identities of terminal devices to an indication of theirinherent mobility. In this case the terminal device can in effectprovide a base station with an indication of its mobility and theassociated reliability by simply providing the base station with anindication of its identity. The base station receiving the indication ofthe terminal device identity is able to refer to the table linkingidentities of the terminal devices to their inherent mobility propertiesto establish the relevant mobility parameters for the terminal device.

In step S6 the base station to which the mobility status and mobilitystatus reliability have been conveyed can establish one or moreconfiguration parameters defining one or more aspects of how theterminal device will operate within the wireless telecommunicationssystem in a manner which takes account of both the indication ofmobility status and the indication of reliability for the mobilitystatus received from the terminal device. For example, the base stationmay be arranged to configure the terminal device for operation withinthe wireless telecommunications system in a manner that takes account ofboth the mobility status and the reliability for the mobility status byconfiguring one or more aspects of the operation of the terminal deviceselected from the group comprising: (i) one or more parameters of apower saving state; (ii) one or more parameters of a radio resourcecontrol, RRC, configuration state—for example a power saving state maybe configured for the terminal device to use if it is determined to bestationary (iii) one or more parameters of a discontinuous reception,DRX, mode of operation—for example a slow moving terminal device maybenefit from longer DRX periods since it does not need to performmeasurements as frequently to support handover; (iv) a duration forwhich the terminal device remains in a radio resource connected mode—forexample a device that is typically sending relatively small amounts ofdata on a relatively frequent basis may benefit from being kept inconnected mode for longer periods of time to avoid signalling overheadassociated with RRC Connection establishment, if the terminal device isslow moving or stationary (so there is little or no handover signallingoverhead) the network may configure its internal inactivity timer tolonger periods of time in order to keep the terminal device in aconnected state; (v) cell reselection parameters—for example a longerT_(reselection) for slower moving terminal devices; (vi) measurementparameters and configuration—for example a shorter time-to-trigger forhandover measurements when the terminal device is moving faster and/ordisabling handover measurements if a terminal device is determined to bestationary (vii) radio bearer or transport and physical channelconfiguration—for example a slower moving terminal device may sufferless reception error than a faster moving terminal device, so could beconfigured with a higher data rate.

As schematically indicated in FIG. 3 in step S7 the base station 504 andthe terminal device 508 may proceed to communicate with oneanother/operate within the wireless telecommunications system inaccordance with conventional techniques but with the terminal deviceconfiguration based, at least in part, on the determined mobility statusand reliability of the mobility status. Once the relevant configurationparameters have been determined they may be communicated between thebase station and terminal device in accordance with conventionaltechniques. In some circumstances it may not be necessary for the basestation to communicate specific configuration parameters to the terminaldevice because the terminal device may be able to independentlydetermine what the configuration parameters selected by the base stationwill be according to the determined mobility status and reliabilityindications conveyed to the base station.

It will be appreciated the processing of FIG. 3 merely represents someparticular example embodiments of the disclosure, and differentapproaches may be taken in other implementations. For example, inanother example implementation the exchange of an indication of mobilitystatus and mobility status reliability might not be associated with RRCconnection signalling. Instead, the base station may, for example, beconfigured to request the terminal device to provide such information onan ad hoc basis, for example when the base station is consideringchanging the configuration parameters for the terminal devicesoperation. In another example, the terminal device may be configured toprovide an indication of its mobility status and associated reliabilityin response to determining a change in its mobility status (for examplebecause it has been placed in or disconnected from a dock).

Furthermore, in the example represented in FIG. 3 the determinedmobility status and the indication of the reliability of the mobilitystatus are schematically indicated as being transmitted together in stepS5. However, in other examples these two indications might betransmitted separately. For example, an indication of what reliabilityshould be attributed to mobility status reports from the terminal device(or by way of a proxy an indication of how the terminal devicedetermines its mobility status) may be a fixed property of the terminaldevice and conveyed to the base station in association with otherwiseconventional terminal device capability signalling.

Furthermore still, it will be appreciated that in some examples themobility status and mobility status reliability may be combined into asingle indication. For example, the mobility status for the terminaldevice may comprise an indicator that may be selected from among aplurality of predefined indicators for identifying different predefinedrelative levels of mobility. Some of the indicators comprising thisgroup may be associated with different levels of reliability. Forexample, the mobility status for a terminal device in one exampleimplementation may be selected from a group comprising:

-   -   high-mobility    -   medium-mobility    -   low-mobility    -   stationary with low-reliability    -   stationary with high-reliability

In this example there are five types of mobility status that may bereported. The first three may broadly correspond with conventionalmobility state estimation parameters in LTE. However, the last two maycorrespond with an extension of these three states to include thepossibility of a terminal determining it is stationary. One state may beused to indicate the terminal device has determined it is stationary ina manner which has relatively low reliability (e.g. based oncell-reselection/handover counting) while the other state may be used toindicate the terminal device has determined it is stationary in a mannerwhich has relatively high reliability (e.g. based on a fixed deviceproperty or the terminal device being (at least temporarily) connectedto something at a fixed location (such as a docking station)). The basestation may be configured to handle terminal devices reporting they arestationary with low-reliability differently from terminal devicesreporting they are stationary with high-reliability. For example, for aterminal device reporting itself to be stationary with low-reliability,the base station may configure handover measurements, or avoid using apower-saving state, whereas for a terminal device reporting itself to bestationary with high-reliability, the network might not configure theterminal device to make handover measurements, and could potentiallymaintain the terminal device in a connected state for a long time (withother terminal device parameters set accordingly), or configure theterminal device to use a particular power-saving state. As noted above,different manners of determining mobility may be associated with low-and high-reliability according to a predefined association. For example,in one extreme the “stationary with high-reliability” indication mayonly be available for terminal devices which have “stationary” as aninherent device property.

Thus there has been described a wireless telecommunication system thatcomprises a base station and a terminal device (UE). The UE isconfigured to determine its mobility status and an associatedreliability, e.g. an indication of the extent to which the UE is movingand the confidence in this determination. In some cases the reliabilitymay be based on how the UE determined its mobility status. For example,if the UE determined itself to be of relatively low mobility because ithas an internal configuration setting indicating it is deployed in afixed position, the reliability of this mobility status may beconsidered to be greater than if the UE determined itself to be ofrelatively low mobility because it has not recently undergone many basestation handovers/cell reselections. The UE is configured to convey anindication of the mobility status and the reliability to the basestation. The base station may then configure the UE for operation withinthe wireless telecommunications system in a manner that takes account ofboth the mobility status and the reliability for the mobility status.This can help optimise configuration settings for the UE which depend ondevice mobility.

Further particular and preferred aspects of the present invention areset out in the accompanying independent and dependent claims. It will beappreciated that features of the dependent claims may be combined withfeatures of the independent claims in combinations other than thoseexplicitly set out in the claims.

Thus, the foregoing discussion discloses and describes merely exemplaryembodiments of the present invention. As will be understood by thoseskilled in the art, the present invention may be embodied in otherspecific forms without departing from the spirit or essentialcharacteristics thereof. Accordingly, the disclosure of the presentinvention is intended to be illustrative, but not limiting of the scopeof the invention, as well as other claims. The disclosure, including anyreadily discernible variants of the teachings herein, define, in part,the scope of the foregoing claim terminology such that no inventivesubject matter is dedicated to the public.

Respective features of the present disclosure are defined by thefollowing numbered paragraphs:

Paragraph 1. A method of operating a terminal device for communicatingwith a base station in a wireless telecommunications system, the methodcomprising: determining a mobility status for the terminal device and anassociated reliability for the determined mobility status; conveying anindication of the mobility status and an indication of the reliabilityfor the mobility status to the base station; and configuring theterminal device for operation within the wireless telecommunicationssystem in a manner that takes account of both the mobility status andthe reliability for the mobility status.

Paragraph 2. The method according to paragraph 1, wherein the step ofconfiguring the terminal device for operation within the wirelesstelecommunications system in a manner that takes account of both themobility status and the reliability for the mobility status comprisesreceiving configuration information from the base station wherein theconfiguration information is determined by the base station in a mannerthat takes account of both the mobility status and the reliability forthe mobility status.

Paragraph 3. The method according to any preceding paragraph, whereinthe indication of the mobility status for the terminal device comprisesan indicator selected from a group comprising a plurality of indicatorsfor identifying different predefined relative levels of mobility.

Paragraph 4 The method according to paragraph 3, wherein the indicationof the mobility status for the terminal device comprises an indicationthat the terminal device is determined to be have a relatively lowmobility.

Paragraph 5 The method according to any preceding paragraph, wherein theindication of the mobility status for the terminal device comprises anindication that the terminal device is determined to be stationary.

Paragraph 6. The method according to any preceding paragraph, whereinthere are a number of different ways for terminal devices operating inthe wireless telecommunications system to determine their mobilitystatus, and the indication of the reliability for the mobility statuscomprises an indication of the manner in which the mobility status hasbeen determined.

Paragraph 7. The method according to any preceding paragraph, whereinthe indication of the reliability for the mobility status comprises anindication of whether the mobility status has been determined fromsignalling exchanged between the terminal device and one or more basestations in the wireless telecommunications.

Paragraph 8. The method according to any preceding paragraph, whereinthe mobility status comprises an indication of whether the mobilitystatus has been determined by counting handovers and/or cellreselections between base stations for the terminal device.

Paragraph 9, The method according to any preceding paragraph, whereinthe step of conveying an indication of the mobility status and anindication of the reliability for the mobility status to the basestation comprises conveying an indication of a mobility statusassociated with a pre-defined reliability.

Paragraph 10. The method according to any preceding paragraph, whereinthe mobility status for the terminal device is predefined for theterminal device.

Paragraph 11. The method of paragraph 10, wherein an indication of thepredefined mobility status for the terminal device is available to thebase station and conveying the indication of the mobility status and theindication of the reliability for the mobility status to the basestation comprises conveying an identifier for the terminal device.

Paragraph 12. The method of paragraph 10 or 11, wherein an indication ofthe predefined mobility status for the terminal device is stored inassociation with a network part of the wireless telecommunicationssystem.

Paragraph 13. The method according to any preceding paragraph, whereinthe mobility status for the terminal device and/or the reliability forthe mobility status is determined from a plurality of previouslydetermined locations for the terminal device.

Paragraph 14. The method according to any preceding paragraph, whereinthe mobility status for the terminal device and/or the reliability forthe mobility status is determined from the terminal device beingconnected to an element of its environment.

Paragraph 15. The method according to any preceding paragraph, whereinthe indication of mobility status for the terminal device and/or theindication of reliability for the mobility status is conveyed by theterminal device to the base station in response to the terminal devicedetermining there has been a change in mobility status and/or thereliability for the terminal device as compared to a previously conveyedindication of mobility status for the terminal device and/or indicationof reliability for the mobility status.

Paragraph 16. The method according to any preceding paragraph, whereinconfiguring the terminal device for operation within the wirelesstelecommunications system in a manner that takes account of both themobility status and the reliability for the mobility status comprisesconfiguring an aspect of the operation of the terminal device selectedfrom the group comprising: (i) one or more parameters of a power savingstate; (ii) one or more parameters of a radio resource control, RRC,configuration state (iii) one or more parameters of a discontinuousreception, DRX, mode of operation; (iv) a duration for which theterminal device remains in a radio resource connected mode; (v) cellreselection parameters; (vi) measurement parameters and configuration;and (vii) radio bearer or transport and physical channel configuration.

Paragraph 17. The method according to any preceding paragraph, whereinthe indication of the mobility status and/or the indication of thereliability for the mobility status is conveyed to the base stationduring a radio resource connection setup procedure.

Paragraph 18. A terminal device for communicating with a base station ina wireless telecommunications system, wherein the terminal devicecomprises a controller unit and a transceiver unit configured to operatetogether to determine a mobility status for the terminal device and anassociated reliability for the determined mobility status; to convey anindication of the mobility status and an indication of the reliabilityfor the mobility status to the base station; and to configure theterminal device for operation within the wireless telecommunicationssystem in a manner that takes account of both the mobility status andthe reliability for the mobility status.

Paragraph 19. Circuitry for a terminal device communicating with a basestation in a wireless telecommunications system, wherein the circuitrycomprises a controller element and a transceiver element configured tooperate together to cause the terminal device to determine a mobilitystatus for the terminal device and an associated reliability for thedetermined mobility status; to convey an indication of the mobilitystatus and an indication of the reliability for the mobility status tothe base station; and to configure the terminal device for operationwithin the wireless telecommunications system in a manner that takesaccount of both the mobility status and the reliability for the mobilitystatus.

Paragraph 20. A method of operating a base station for communicatingwith a terminal device in a wireless telecommunications system, themethod comprising: receiving from the terminal device an indication of adetermined mobility status for the terminal and an indication of anassociated reliability for the mobility status; and configuring theterminal device for operation within the wireless telecommunicationssystem in a manner that takes account of both the mobility status andthe reliability for the mobility status.

Paragraph 21. A base station for communicating with a terminal device ina wireless telecommunications system, wherein the base station comprisesa controller unit and a transceiver unit configured to operate togetherto receive from the terminal device an indication of a determinedmobility status for the terminal and an indication of an associatedreliability for the mobility status; and to configure the terminaldevice for operation within the wireless telecommunications system in amanner that takes account of both the mobility status and thereliability for the mobility status.

Paragraph 22. Circuitry for a base station communicating with a terminaldevice in a wireless telecommunications system, wherein the circuitrycomprises a controller element and a transceiver element configured tooperate together to cause the base station to receive from the terminaldevice an indication of a determined mobility status for the terminaland an indication of an associated reliability for the mobility status;and to configure the terminal device for operation within the wirelesstelecommunications system in a manner that takes account of both themobility status and the reliability for the mobility status.

REFERENCES

[1] ETSI TS 122 368 V11.6.0 (2012-09)/3GPP TS 22.368 version 11.6.0(Release 11)

[2] ETSI TS 136 304 V11.5.0 (2013-09)/3GPP TS 36.304 version 11.5.0(Release 11)

[3] ETSI TS 136 331 V11.5.0 (2013-09)/3GPF TS 36.331 version 11.5.0(Release 11)

[4] Holma H. and Toskala A, “LTE for UMTS OFDMA and SC-FDMA based radioaccess”, John Wiley and Sons, 2009

What is claimed is:
 1. A network node for communicating with a terminalin a wireless telecommunications system, the network node comprising:circuitry configured to acquire a first indication of a mobility statusfor the terminal and a second indication of a reliability for themobility status, settings of the second indication including a highsetting and a low setting; and configure the terminal based on the firstindication of the mobility status and the second indication of thereliability for the mobility status, wherein the first and secondindications are different, and wherein, when the first indication has afirst setting, the network node configures the terminal to be in apower-saving state when the second indication of the reliability for themobility status has the high setting and to make handover measurementswhen the second indication of the reliability for the mobility statushas the low setting.
 2. The network node of claim 1, wherein thecircuitry is further configured to: receive subscriber identificationinformation from the terminal device; and acquire the first indicationof the mobility status of the terminal and the second indication of thereliability for the mobility status from a core network element based onthe subscriber information received from the terminal device.
 3. Thenetwork node of claim 1, wherein the circuitry is further configured to:receive identification information from the terminal device; anddetermine the first indication of the mobility status of the terminaland the second indication of the reliability for the mobility statusfrom a core network element based on a table using the identificationinformation received from the terminal device.
 4. The network node ofclaim 1, wherein the mobility status for the terminal is determined froma plurality of previously determined locations for the terminal, and theindication of the reliability for the mobility status is determined froma plurality of previously determined locations for the terminal.
 5. Thenetwork node of claim 1, wherein the first setting of the firstindication is stationary, the first setting of the second indication ishigh reliability, and the second setting of the second indication is lowreliability.
 6. The network node of claim 1, wherein the mobility statusfor the terminal is determined from the terminal being connected to oneor more base stations of the wireless telecommunications system, and theindication of the reliability for the mobility status is determined fromthe terminal being connected to one or more base stations of thewireless telecommunications system.
 7. The network node of claim 1,wherein the mobility status includes an indication that the terminal hasa mobility below a predetermined threshold value.
 8. The network node ofclaim 1, wherein the mobility status includes an indication whether theterminal is stationary or mobile.
 9. The network node of claim 1,wherein the indication of the reliability for the mobility statusindicates a method used to determine the mobility status of theterminal.
 10. The network node of claim 1, wherein the indication of thereliability for the mobility status indicates whether the mobilitystatus is determined from signalling exchanged between the terminal andone or more base stations in the wireless telecommunications system. 11.The network node of claim 1, wherein the mobility status is determinedbased on an actual number of handovers and/or cell reselections betweenthe terminal and base stations of the wireless telecommunicationssystem.
 12. The network node of claim 1, wherein the mobility status isdetermined based on an expected number of handovers and/or cellreselections between the terminal and base stations of the wirelesstelecommunications system.
 13. The network node of claim 1, wherein themobility status for the terminal is predefined, and the circuitry isconfigured to acquire the indication of the mobility status for theterminal based on an identifier of the terminal from a memory, which isconfigured to store the mobility status in association with theidentifier of the terminal.
 14. The network node of claim 1, whereinconfiguring the terminal for operating in the wirelesstelecommunications system based on the mobility status and theindication of the reliability for the mobility status includesconfiguring an aspect of the operation of the terminal selected from thegroup comprising: one or more parameters of a power saving state; one ormore parameters of a discontinuous reception (DRX) mode of operation;cell reselection parameters; measurement parameters and configuration;and radio bearer or transport and physical channel configuration. 15.The network node of claim 1, wherein configuring the terminal foroperating in the wireless telecommunications system based on themobility status and the indication of the reliability for the mobilitystatus includes configuring an aspect of the operation of the terminalselected from the group comprising: one or more parameters of a radioresource control (RRC) configuration state; and a duration for which theterminal remains in RRC connected mode.
 16. A network node forcommunicating with a terminal in a wireless telecommunications system,the network node comprising: circuitry configured to acquire a firstindication of a mobility status for the terminal, the first indicationindicating an actual or expected number of handovers and/or cellreselections between the terminal and base stations of the wirelesstelecommunications system, and a second indication of a reliability forthe mobility status, settings of the second indication including a highsetting and a low setting; and configure the terminal based on the firstindication of the mobility status and the second indication of thereliability for the mobility status, wherein the first and secondindications are different, and wherein, when the first indication has afirst setting, the network node configures the terminal to be in apower-saving state when the second indication of the reliability for themobility status has the high setting and to make handover measurementswhen the second indication of the reliability for the mobility statushas the low setting.
 17. The network node of claim 16, wherein the firstsetting of the first indication is stationary, the first setting of thesecond indication is high reliability, and the second setting of thesecond indication is low reliability.
 18. A method performed by anetwork node for communicating with a terminal in a wirelesstelecommunications system, the method comprising: acquiring a firstindication of a mobility status for the terminal, the first indicationindicating an actual or expected number of handovers and/or cellreselections between the terminal and base stations of the wirelesstelecommunications system, and a second indication of a reliability forthe mobility status, settings of the second indication including a highsetting and a low setting; and configuring the terminal based on thefirst indication of the mobility status and the second indication of thereliability for the mobility status, wherein the first and secondindications are different, and wherein, when the first indication has afirst setting, the network node configures the terminal to be in apower-saving state when the second indication of the reliability for themobility status has the high setting and to make handover measurementswhen the second indication of the reliability for the mobility statushas the low setting.
 19. The method of claim 18, wherein the firstsetting of the first indication is stationary, the first setting of thesecond indication is high reliability, and the second setting of thesecond indication is low reliability.
 20. A network node forcommunicating with a terminal in a wireless telecommunications system,the network node comprising: circuitry configured to configure theterminal based on a first indication of a mobility status for theterminal and a second indication of a reliability for the mobilitystatus, settings of the second indication including a high setting and alow setting, wherein the first and second indications are different, andwherein, when the first indication has a first setting, the network nodeconfigures the terminal to be in a power-saving state when the secondindication of the reliability for the mobility status has the highsetting and to make handover measurements when the second indication ofthe reliability for the mobility status has the low setting.
 21. Thenetwork node of claim 20, wherein the first setting of the firstindication is stationary, the first setting of the second indication ishigh reliability, and the second setting of the second indication is lowreliability.
 22. A method performed by a network node for communicatingwith a terminal in a wireless telecommunications system, the methodcomprising: configuring the terminal based on a first indication of amobility status for the terminal and a second indication of areliability for the mobility status, settings of the second indicationincluding a high setting and a low setting, wherein the first and secondindications are different, and wherein, when the first indication has afirst setting, the network node configures the terminal to be in apower-saving state when the second indication of the reliability for themobility status has the high setting and to make handover measurementswhen the second indication of the reliability for the mobility statushas the low setting.